Facebook shareholders got the long-awaited gift of liquidity last week when Russia’s Digital Sky Technologies began buying up to $100 million of Facebook common stock from current and former employees.

The latter group however, may end up with bupkus, as it turns out that the program puts ex-employees at the back of the line.

Only after all of Facebook’s current employees have had a chance to sell their stock to DST for $14.77 a share can former employees step forward to cash out their shares, according to person familiar with the matter.

That’s sensible enough, since the point of the program is to help Facebook’s loyal workers get funds to defray the cost of living in costly Palo Alto, California, and not to line the pockets of people who jumped ship.

But it means that former Facebookers may not get a chance to reap the benefits of their stakes in the world’s largest Internet social network. If Facebook’s current employees use up the $100 million that DST has committed to buying shares, ex-Facebook shareholders are out of luck. And forget about cashing out through an IPO any time soon.